It sounds like you were either not around or didn't use Google in the early 00s. Back then, there was a very clear, bright color difference between ads and organic search results: a yellow bar at the top with at most two ads, and a side bar. But organic results were easy to identify and took up the majority of screen real estate.
Now, when I search any even slightly remotely commercial search term on mobile, about the entire first page and a half of results are ads. Yes, they're identified with a "Sponsored" message, but as you can see from the "evolution" link the other commenter replied, this was obviously done to make the visual treatment between ads and organic results less clear.
The reason I'm thrilled about Google finally getting competition in their bread-and-butter is not because I want them to fail, but I want them to stop sucking so bad. For about the past 10 or so years Google has gotten so comfy with their monopoly position that the vast majority of their main search updates have been extremely hostile to both end users and their advertisers as Google continually demands more and more of "the Google tax" by pushing organic results down the page.
In the meantime I've switched to Bing, not because I think Microsoft is so much better, because I desperately want multiple search alternatives.
To quote from the above, here's what they said in the beginning: "we expect that advertising funded search engines will be inherently biased towards the advertisers and away from the needs of the consumers"
The tweet you linked was from an outage that lasted 30 minutes, it's pretty disingenuous of you to try and pass that off as status quo.
I do agree however that the labeling has gotten less prominent over time. I don't however agree that it has become subtle enough to considered indistinguishable from search results.
> I don't however agree that it has become subtle enough to considered indistinguishable from search results.
This is what it looks like on mobile. A tiny "sponsored" text is the only thing that distinguishes ads from search results: https://imgur.com/a/WOk4NdR
Before Google, search engines didn't do this. Paid results were indistinguishable from organic results.
Here's an example --> https://imgur.com/a/bSJTBeD
If you have a counter-example, please share!